Manufacture of metal-phthalocyanines



Apri 4, 1939.

M. A. DAHLEN ET AL MANUFA C'IVURE OF METAL PHTHALOCYANINES Filed March 5, 1937 INVENTORS ATTORNEY.

Patented Apr. 4, 1939 UNITED STATES .PATENT'or-Fica 2,153,300 MANUFACTUBE 0F METAL-PHTHALO- v CYANINES Miles a. Damen and stanley a. Derrick, wilmington, Delaassignors to E. I. du .Pont de Nemours & Company,

poration of Delaware Application Maren 5,

3 Claims.

This invention relates to an improved process for the manufacture of metal-phthalocyanlnes from phthalonitrile. l

The reaction 'between phthalonitrile and a metal yielding substance, such as copper powder or cuprous chloride, at elevated temperature, is highly exothermic. When practiced on a large scale the high temperature within the charge risesl so high as to cause definite injury to the quality l of the pigment, both in strength and in brilliance.

as to be dangerous to operate on 'anybut a small scale.

To avoid the above hazards-'several attempts wv were made in the art. According to one of these attempts, the reaction was carried out i n shallow4 pans, with the disadvantage, however, that the quantity produced `per unit apparatus in a given time is very small and therefore not very eco- ,20 nomical.

In Aanother attempt at removing the'hazard, it was proposed to carry out the reaction in the presence of inert solid diluents such as sodium chloride or silicon dioxide. This method has -in turn the disadvantage that the product is obtained in admixture with foreign material from which it must be purliied except for special pur-l poses wherein the foreign material lis not objectionable. Furthermore, our'tests on the above manner, deriving the greatest lpossible efllciency from a. given set of apparatus in a given time.

' AOther'and'further objects of this invention will appear as the description proceeds. 45 According to our invention the temperature of the reaction mass is controlled by feeding the reactants into the reacting chamber portion-wise, thereby avoiding undue development of heat in a short time. At the same time, thev apparatus 0 .is used to its maximum eillciency inasmuch as the entire quantity of initial material correspond- .ing to the capacity of the apparatus is entered in a relatively short time and but a single step of baking and recovery is applied to the entire 55 mass.

Furthermore, thereaction becomes'so vigorous process show that the improvement is not always gton, Del.; a cor- 1937, serial No. l 129,281

(ci. asosw4 More particularly, we prefer to carry out the reaction in a rotary vessel provided with means v for external heating, and provided internally with means, for grinding the reaction mass asv the reaction proceeds.- We prefer to initiate the reaction with a quantity yof phthalonitrile and.

metal-yielding substance corresponding to about one-third or less of the optimum quantity for the given apparatus. Then, after the initial spurt of the reaction, we feed in an additional quantity' of phthalonitrile andV metal-yielding substance, allowing the new reaction Vtopass beyond its vigorous stage, and'then again add anew quantity of the reaction materials, repeating the cycle batch has been used up.

Our invention is also susceptible of modication whereby the material may be fed in in a con.

tinuous manner. f v.

Our invention is applicable to the manufacture oi metal-p hthalocyanines by starting with phthalonitrile and a suitable metal-.yielding sub- Auntil the entirematerial designed for a single stance, or to the manufacture of substituted metal-phthalocyanines by starting with the correspondingly substituted phthalonitriles such asv monoor dihalogen phthalonitrile, mono-.- or dior other derivatives. 'I'he phthalonitrile employable in our process may be in molten or solid v state,l and when in solid s tate it may be ,pow-

stantial weight and castinto a shape that will best suit the particular apparatus employed.

As for the metal-yielding substance, our invention may be applied to the manufacture of any metall-phthalocyanine by the `use of either the corresponding metals or compounds of said metals, but for the sake of simplicity the invention will be hereinbelow illustrated' by specific" application to theI manufacture of copperphthalocyanine. f The invention will be understood more fullyby catlon'being particularly suited for the use of molten phthalonitrile as initial material'. Figure 2 is a similar elevation showing a modimethyl phthalonitrile, or the corresponding nitrodered or it may be in the form of ingots of sub reference to the following examples and to the.

- adapted for the use of phthalonitrile in powder form.

O Referring now to Figures 1 and 2 in detail, I

'5 is a hollowdrum, hereinafter referred to as a y rotary. baker, mounted on shaft segments 2, V3

. extendingoutward from each end of the drum,

' into the aligned bearings I, l to form a rotatable Vsupport for the drum. The segment 3 of this shaft is hollow and leads to the interior of the drum. I'he rotary baker contains a number-of tumbling elements 9, such as metal rods. Entering into the hollow shaft-segment 3 is .an insulated, steam jacketed pipe 5 which is adapted to convey molten material from the phthalonitrile melt tank. I. The latter is provided with steam coilv 'I and valvel 8. The, shaft segment '2 is connected to a pulley Il or other suitable means for rotating the drum upon its shaft segments during the course of the reaction.

1The rotary baker is heated by a gas iet Il, which is provided with means (not shown) for circulating air around the shaft wherebyto control the temperature produced therein. A thermocouple device Il, I3 connected electrically to the inside of the drum by the aid of slip rings I! indicates the temperature within the drum.

The baker is also provided with a grated opening I l, (shown more clearly in Fig. v2), normally covered by 'a plate I1, whereby its contents may be emptied Vonto avfilter screen I8.

'Ihe baker, gas jet and lter screen are all enclosed in a suitable housing or oven 26, provided withl an entry door (not shown) and a vent or chimney 2|.

Over the end of the hollow shaft segment 3, including part oi' the feed pipe 6 fits' a loose sleeve 22, provided with a fan 28, leading to an exhaust pipe (not shownl., wherebyto carry off any fumes issuing from the hollow drum.

In the modication shown in Fig. 2, the melt-- ing tank i is 'replaced by a hopper 30 and screw feed `3| whereby material in solid but powder 'form can be conveyed to the apparatus instead of themolten form. Otherwise, the construction is the same as in IHg. l, including the oven, gas Jet, thermocouple and exhaust fan, which, however, were omitted from Fig. 2, for the sake of simplifying the view and showing the other details to betteradvantage.

Both the /melting tank with its feed line and the hopper device with its screw conveyor t slidably into the hollow shaft segment 3, and may be removed therefrom .it will, therebyv providing a vdirect entry into the hollowshaft,

-through' which the drum may be charged manually with solid chunks of material, if so desired. In the lexamples given below the parts are by weight. l .o It will beunderstood that except for the differences in the feeding device, the apparatus of Figs. 1 and 2 are identical 'and the festin-es shown separately in the two gures are actually present' jjointly in each of the modifications. Thus, each modification is surrounded by a housing and is provided with heating means (gas iet) air circulation means, exhaust fan, etc., as explained in conjunction with Flg. l. mkewisaeach modification is provided with a'grated opening, cover 70 plate and filter screen, as explained in conjunction with Fig. 2.' In leither `modication the phthalonitrile feeding v.device may be removably into the hollowshaft. andmay be replaced at will by one of theother types of feeding l cation oi' invention which is particularlyis of course necessary only where the molten form Elample 1 50 parts o f phthalonitrile and 7 parts of copper powder are introduced into the rotary baker I (Fig. l). Agitation is started and the temperature is raised tov 220 C. as rapidly as possible. A vigorous reaction takes place and the temperavture increases to 240 C. After the reaction lhas subsided, another 'l parts of copper powder are added through the hollow shaft, the phthalonitrile feeding device 8 5 being temporarily slid A Aout of the hollow shaft for this purpose, to provide manual access thereto. Meanwhile, 100 parts of'phthalonitrile are melted in the auxiliary melt ytank 6. The phthalonitrile feeding device is now moved back into place, and 50 parts of the molten material are added to the jacketed line 5 extending into the baker `through the hollow shaft. A new spurt of reaction takes place and when this has subsided, a third 'I-parts portion of copper powder and the remainder of the molten phthalonitrile are added in the same manner as above. The baker is maintained at 230 to 240 C. during these additions. After all active exothermic reaction vis over, the charge is baked for four hours at 230 C. to insure completion of the reaction.

After purification of the reaction mass by dissolving in concentrated sulfuric acid and drowning in hot Water, a good yield of pigment of excellent quality ast brilliance and strength is obtained. l y

Example 2 300 parts of -vphthalonitrile and parts of copper powder are mixed intimately in a ball mill. The reactionv is carried out ina long iron tube- Aclosed at one end and heated externally by means of an oil bath. The contents of the tube and the oil bath both are -agitated.

'I'he inside temperature of the tube is raised to 240 C. l0 parts of the mixture from the ball mill are added, whereupon the temperature which at first drops to 220 C. rises immediately -to 245 C.

Additions are made further at intervals of 4 -to '5 'minutes until all of the charge has been added, the inside temperature fluctuating between 220 and 250 C. Thereupon the charge is baked for a tota-l of two hours.

After purification by solution in concentrated sulfuric acid and drowning in hot water, a good yield of high quality pigment is obtained.

Example' 3 28 parts of copper powder are charged into a" rotary baker and the temperature brought to 240 C. 200 parts of phthalonitrile are cast into cylfumes of the nitrile issue from the shaft in the form 'of a white cloud. After all the nitrile has been added, the baker is agitated for another two hours at 240 C.

'After purification by solution in Concentrated sulfuric acid and'drowning in hot water, avgood yield of high quality pigment is obtained.

Example 4 50 parts of phthalonitrile and 'I parts of cop- 5 per powder are charged int'othe rotary baker and rt wm be understood that although the above' examples illustrate the invention only in the case 1 of copper powder, it is likewise applicable to the manufacture .of other metal phthalocyanines by a0 the use oi other metals, for instance, manganese,

tungsten, chromium, iron, nickel, cobalt, magnesium, lead, cerium, tin, bismuthrandmolybdenum. Likewise, instead of the free metals, compounds capable of yielding these metals at elevated temperature may be employed, for instance,

cuprouschloride, cuprous and cupric oxides, cu-

pric sulfide, cupric acetate, cupric sulfate, stan-' nous chloride, cobaltous chloride, nickelous chloride, aluminum' chloride, barium chloride, copper nitrate and molybdenum oxide.

Of course, it will be realized that when using` a salt of a metal insteadlof the free metal in the above reaction, the temperature is regulated so as to correspond to the optimum for the par-4 ticular metal compound. y For instance, when cuprous chloride is employed, the preferred temperature is between 150 and 170 C.; when aluxvninum chloride is used; the preferred temperature is between 230 and 250 C. In general, the optimum temperature falls as a rule .between 150 and 250 C., and-can be determined by observation in each particular case.

In lieu of, phthalonitrile, substitutedphthalonitriles may be employed, for instance, 3-methylphthalonitrile, 3-chloro-lzlhtlialonitrile,v 3,4-dichloro-phthalonitrile, 3*-nitro-phthalonitrile, 3- sulfo-phthalonitrile. etc.

lIt will be'clearnow that by thoabove invention we have provided an improved process for o manufacturing metal-phthalocyanines whereby excessive generation of heat, with resultant hazard of explosions, is eliminated'. Furthermore, the product obtained is superior in quality,y particularly as to brilliance 'and strength, to products which are` obtained without careful temperature control. vOur process also is characterized by high eilciency and economy inasmuch as it makesmaximum vuse of apparatus and time.- Finally, our process is adapted for conversion into a continuous Aprocess whereby both the initial material is continuously fed into the apparatus and the reaction product continually removed.vv I

- We claim:

1. A process for the manufacture of copper yph'thalocyanine which comprises heating togetherr tity of phthalonitrile, likewise avoidingthe development of atemperature-'above 250 C. and repeating the cycle until the apparatus is sub- -fstantially full of reacting materials toits optimum capacity, then baking the entire mass at a temperature between 220 and 250 C. and recovering the reaction mass.l l

2. The process of manufacturing vcommi: phthalocyanine which comprises heating a vessel containing copper powder to'a temperature between 220 and 250 C., then adding intovthe vessel phthalonitrile in the form 'of solid units which-are adapted to react with the copper to form copper-phthalocyanine inside the heated vessel, the material being fed in at suola a rate that each preceding unit has been'substantially completely consumed before the addition of the next solid unit, and finally `baking the entire contents of the vessel at a temperaturel between 220` and 250 C. for a period of 2 ,to 5 hours.

3. A process as in claim 1, wherein in each cycle an additional quantity of copper is added jointly withl the phthalonitrile.

MILE A. Dammi. STANLEY R. DITRICK. 

